test_abort_accept_after_handshake times out on Fedora 33

[bhalevy]

After upgrading to Fedora 33, that installed kernel kernel 5.6.19-300.fc32.x86_64
I rebuilt seastar from scratch and ran the unit tests. All pass except for tls_test that times out consistently.
I added some BOOST_TEST_MESSAGEs and it turns out the read() call does not return:

seastar/tests/unit/tls_test.cc

Line 250 in d2c0df0

auto buf = in.read().get0();

[bhalevy]

Reproduced with kernel 5.8.16-300.fc33.x86_64

The test passes when building and running in the scylla dbuild docker (image docker.io/scylladb/scylla-toolchain:fedora-32-20200910)
gcc version in dbuild is 10.2.1-1 while on my laptop it's 10.2.1-5
both have /usr/lib64/libgnutls.so -> libgnutls.so.30.28.1
and actually all the other dynamic libraries look the same.

[bhalevy]

Hmm, digging a bit deeper revealed a different glibc library version:

bhalevy@lt scylla$ ./tools/toolchain/dbuild -- ls -l /usr/lib64/libc.so.6
lrwxrwxrwx. 1 root root 12 Jul 16 05:27 /usr/lib64/libc.so.6 -> libc-2.31.so
bhalevy@lt scylla$ ls -l /usr/lib64/libc.so.6
lrwxrwxrwx. 1 root root 12 Aug  6 17:47 /usr/lib64/libc.so.6 -> libc-2.32.so

[bhalevy]

@avikivity wrote:

I traced this to

     if (status & GNUTLS_CERT_INVALID) {
         throw verification_error(

cert_status_to_string(gnutls_certificate_type_get(*this),
status));
}

My guess is that someone tightened the accepted encryption algorithms so
that the test certificates are no longer accepted.

[bhalevy]

@elcallio please look into this